Individual tumors exhibit distinct characteristic natures, and their biological properties are not necessarily identical even though the basic principle of oncogenesis is the same. Rapid advances in the understanding of cancer from a molecular biological and molecular genetic perspective in recent years have opened the way to an explanation of oncogenesis and tumor cell biology on the genetic level.
Hepatoblastoma is a malignant hepatoma occurring in infants with the highest frequency and 70% of the infants develop it before they reach two years of age. The infants who have been afflicted with hepatoblastoma generally experience a systemic decline in health and exhibit a large mass in the right upper abdomen. In hepatoblastoma if its detection is at an early stage, there will be some hope of long-term survival through chemotherapy and surgical operation. When the detection is late, complete cure will be difficult; therefore, early detection is desired.
AFP (alpha-fetoprotein) in blood is the only hepatoblastoma marker in the diagnosis of hepatoblastoma that has been known to date. Hepatoblastoma has thus been diagnosed by detection or quantification of AFP. However, it is known that the blood concentration of AFP rises not only in hepatoblastoma but also in hepatoma. There is also a drawback that its specificity is low and its values have sometimes been elevated in diseases other than hepatoblastoma or hepatoma (such as liver cirrhosis). Accordingly, AFP is insufficient for the use as a tumor marker specific for hepatoblastoma. A problem has existed that there is no other way but the ultimate collection of part of the carcinoma tissue followed by its pathological and histological diagnosis.